<textarea distributed>: An illustrated intro to CRDTs

Nodevember 2016.

[Full text of this talk](https://github.com/jorendorff/talks/blob/master/textarea-distributed/textarea-distributed.md) (much better than slides).

[Video of this talk](https://www.youtube.com/watch?v=vCkSLX7nR9Y) (still better than slides).

Transcript

4. shape of time can get strange
14. …and that’s what I want to show you today. …go to this URL…
15. I do want to take a moment before we begin to ask you to participate in the spirit of the thing.
16. bit.ly/nv-clobber
18. This is the full state of our shared text editor. just a global string variable a text file is just a string
19. I'm using a library called socket.io to handle networking between the browser and the server, because this talk isn't about networking. - simplest thing I could think of
30. bit.ly/nv-quill
35. bit.ly/nv-univax OK, obviously this works great, but it's not perfect. Let's say we want to collaborate and I'm in London… speed of light
41. …This approach is solid, but it hardcodes network latency right into the app. And it's at this point that I get a little frustrated. Why is this so hard?
42. All we want to do is edit a text file.
43. This should be easy.
44. Instead we keep failing. Just one approach after another stinks,
45. and the kids are starting to ask their mother, "Why is daddy so angry all the time?"
47. We could keep trying things, … So here's my question for you.
49. (discuss before next slide)
50. if you work on web sites long enough… I picked text editing because it's little,…
51. … the speed of light? It is just a fact of life … How do we rephrase this requirement as something possible?
53. And at the end we'll see if I ever actually got my collaborative text editor working, but for now we're going to set that aside …
54. It's a kind of value that a computer knows how to deal with…
55. String Number Array
56. String Number Array text number sequence of values
57. String Number Array text number sequence of values +, slice, replace, etc. +, -, *, Math.sqrt(), etc. arr[i], push, sort, etc.
59. 100% desirable… And that's all a CRDT is… example in a second. data type + ops over network + rules for conflicts …would solve our problem?
60. String Now, a plain old string is not a CRDT. (why) But! … takes space … general pattern … add bookkeeping … not just text … history because conflicts.
61. String +=
62. This paper is only five years old.
63. You can see … same things I’ve been talking about … … rethinking the fundamentals of programming and even of how we think about time … 14th example in this paper …
65. Their implementation is 38 lines of pseudocode. It took me about 200 lines of JS.
69. You would want to optimize.
71. bit.ly/nv-peeredit
77. github.com/jorendorff/peeredit